There has heretofore been a reclining apparatus disclosed in Japanese Patent Application Laid-Open No. 4-90719 which is an application of the present applicant, and a mechanism is disclosed in this publication in which a back member is locked and unlocked via an armrest member in order to adjust the back member of a chair at an arbitrary angle.
However, it is troublesome for a person who sits on a seat member to operate the armrest member in order to adjust the back member at the arbitrary angle.
Moreover, a structure in which the back member is moved with inclination of the back member is desirable in order to obtain a comfortable state in the chair, and the like.
Consequently, the inventor has intensively repeated researches, has found a mechanism in which the seat member has a straight movement property to achieve a smooth forward/backward movement and in which the back member can be adjusted at an appropriate angle in accordance with the position of the seat member without any operation of the armrest member and in which a lock state and unlock stage can be obtained at the angle of the back member, and has provided the mechanism herein.